The disclosure relates to catalytic converters and, more particularly, to an apparatus and method for manufacturing an integrated catalytic converter and flexible endcone assembly.
Catalytic converters are devices incorporated into a mobile vehicle""s exhaust system that reduce the amount of pollutants found in exhaust gases to environmentally harmless levels. The catalytic converter is placed under strenuous operating conditions due to experiencing constant vibrational and oscillating motions, axial and torsional loads, exposure to environmentally unfriendly components exhaust gas, temperature gradients of approximately 1,000xc2x0 C. or more, corrosion, and other typical conditions.
Conventional catalytic converters can experience strain-induced fatigue due to constant vibrational and oscillating motions, axial and torsional loads, and thermal stress during operation. Some conventional exhaust systems for mobile vehicles employ existing flex coupling assemblies that decouple the exhaust system from the engine and/or from other exhaust system components. These assemblies are designed and manufactured separately from the catalytic converter and other exhaust system components.
For example, the flexible coupler apparatus described in U.S. Pat. No. 5,992,896, to Davey et al., and assigned to Senior Engineering Investments AG, employs a pipe inner member disposed within a pair of pipe adapters affixed to adjacent pipe ends, and a pair of spacer members enclosed, respectively, between the opposing ends of the adapter members and pipe inner members. The design further incorporates a biasing means for imparting an axial bias or preload to the coupler apparatus, for providing progressive resistance to compression of the coupler apparatus. A flexible sealing member mechanically connects the adapter members, and, in turn, the pipe ends.
A drawback to the design of Davey et al. is the numerous components required to effectively preclude transmission of vibrations between two pipes in an exhaust system. Davey et al. desire to provide an enhanced, robust coupling apparatus; however, the adapters, additional piece of pipe, sealing members and additional biasing member add weight to the entire exhaust system while also taking up additional space. Conventional vehicle systems maintain stringent space requirements, and preferably seek to incorporate fewer components of lighter weights. For example, exhaust manifold assemblies are now designed to attach between pipes leading from the engine combustion chamber to the catalytic converter, thereby eliminating the need, in some instances, for a single exhaust pipe, or plurality of pipes as contemplated in Davey et al.
The exhaust system also typically experiences several adverse effects stemming from these conventional flexible coupling components. Adverse effects, such as exhaust gas stream flow restrictions, increased weight of the exhaust system, and additional costs are typically attributable to existing flex coupling components.
Accordingly, there exists a need for an apparatus and method for manufacturing a catalytic converter having an integrated flexible coupling device.
The drawbacks and disadvantages of the prior art are overcome by the exemplary embodiments of the integrated catalytic converter/flexible endcone assembly, a method for making the same, as well as a method for treating exhaust gas described herein. The integrated catalytic converter/flexible endcone assembly, comprises a flexible endcone. The flexible endcone has a flexible bellow with a plurality of undulating ribs concentrically radiating outward from an inlet to a periphery. The catalytic converter, which comprises a mat material concentrically disposed around a catalyst substrate and between the catalyst substrate and a shell, is in physical contact and fluid communication with endcone. Essentially, the catalytic converter is sealingly secured to the periphery of the flexible bellows.
The method for manufacturing the integrated catalytic converter/flexible endcone assembly, comprises disposing a catalyst substrate concentrically within a shell. A mat support material is disposed concentrically in between the catalyst substrate and shell. The flexible endcone assembly is secured to the catalytic converter at the periphery of the flexible bellows such that the flexible endcone assembly and the catalytic converter are in physical contact and fluid communication with one another.
The method for treating exhaust gas, comprises passing exhaust gas through the integrated catalytic converter/flexible endcone assembly and catalytically treating one or more constituents in the exhaust gas.